Electric switch



Patented Sept. 9, 1952 Carl A. Schaefer, Milwaukee, Wis., assignor to Square D Company, Detroit, Mich., a corporation of Michigan Application April 29,1949,seria1No.90,441

This invention relates, in general, to adjustable electric switches and more specifically to limit switches for changing the character of an electric circuit supplying a machine when `a moving part of that machine has moved beyond a desiredlimit. Y

Where devices of this type are employed, itis the practice to set the limit switch in' position within the operatve'lir'nits of the moving portion of the machine. The initial positioning frequently, however, determines only roughly the degree-of movement to be permitted to this moving portion and subsequent. finer adjustment is in` that case necessary. This finer adjustment in older devices required changing the position of a4 switch actuating mechanism associated with the moving part, this change occasionally being relatively minute and effected only `with difficulty. Itis, therefore, one object of 'this invention to provide a limit switch which is itself readily ad- .instable tovary the position at which a moving element of an associated machine will cause the` characterof the electric circuit supplying that machine to be changed.

Anotherobject` of this invention is the provision of a limitswitch having an operator whose normal position maybe varied by rotating a shaft having eccentrically mounted means, the shaft being Yan integral part of the switch.

AAnother object of this invention is the provision of anadjustable limit switch provided with an operating member which may be selectively moved inwardly or outwardly to vary the position at which `a moving part of an associated machine operates the switch.

' Other objects and features of the invention will bereadily apparent to those skilled in the art fromv the specification and appended drawing illustrating certain preferred embodiments in whichr` 7 Figure 1 is a rear elevational View of the device of the present invention.

, igure 2 is a vertical sectional view alongthe une 11-11 of Figure 1.

Figure 3` is adetaled sectional view along the line Ill- III of Figure 1,

The device of the present invention comprises straight wire section of sufficient length to permit 11 Claims. (Cl. `200m-4:7)

raising and lowering of the `lever 5, as subseruf.

quently described, without disengagement' of the end 4 therefrom. The lower end of the lever 5 is biased to the left as illustrated in Figure l by I a spring Ii` mounted upon the studs 'l Iand 8 between the lever 5 and the innerwall of'the base 2. The base `is provided with a flanged section through which a plurality of mounting holes 9 extend, and may also have a gasket, II upon the inner surface to insure a sealing connection with a mounting surface or a back cover.

Disposed for reciprocal movement within a hole within the hole I2 as shown at I6. The lower` end of the plunger I3 extends through the upper portionof the base2 and is provided with a s lot into which a retaining ring I1. is fitted which serves to maintain in position a thin washer ,'QI8' against which a spring I9, compressed. between the washer i8 and thev inner surface of the base 2, acts. The spring I9 insures that the lowermost end of the plunger I3A firmly seats upona flange ear 2I of the upper horizontal section of the actuating lever 5. V

There is disposed through a suitable hole through the front wall of the base 2 a rotatable,

shaft 22, having a head at its inner end which seats upon a bossed section 23 of the inner surface of the base.` The inner end` of shaft 22 is provided with a threaded hole whose axis is eccentric to the rotation axis of shaft 22 and which receives a cooperating screw 24 having a collar` 25, about which uppermost end 26 of the actuating lever 5 is rotatably mounted.

The sectionof the rotatable shaft 22 which is exteriorto the front faceof the base is threaded, y

and has a'cutaway portion on which is keyed a controlling and indicating sector 29. `Thenut 3| is threaded on shaft 22 to lock the sector shaft 22in adjusted position.4

The operation of the device will now described:

`When the moving part of the associatedfm chine which it is desired to restrict within certain limits, or'a cam or push .rod cooperating therewith, reaches the limiting position, this part.

or cooperating device moves theplunger' i3. in-

ward against. nge earV 2I'to move-Iactuatingy lever 5 in a counterclockwise direction (Figure `1) against the bias of the spring 6, The lower end 29 and the numeral 28. It will readily be seen that rotation of the shaft 22 will cause the axis 2B to der. scribe an arc about the axis 21, thus effectively raising and lowering the collar 25 and actuating@- lever V5. This raises and lowers the ear 2l to cause the plunger. I3, which is biased to contact the projection 2| by the spring I9, to project a. further or lesser distance beyond the'u'pp'er face' of the bushing I4 and therefore adjusts the point e of operation of switch l'."y In adjustedr position the parts are again locked bythe screw 3l. l

While certain preferred embodiments -of the invention have been specifically disclosed, -it is understood that the. invention is not limited thereto, as many'variations will be readily ap-v parent to those skilled in the art and the inventionis Vto be given its broadest possible interpre-V tation' within the terms of the following claims.

What is claimed is: v

1A. In a limit switch, electrical switching means, a movable actuator for said switching means, an operator for said actuator, rotatable nieans, and means eccentric to the axis of .rotation of said rotatable means and movable thereby to shift the Yposition of said actuator upon rotation of said rotatable means to change the normal position of 'said operator.

rotatable means, means eccentric to the axis vof rotation'of said rotatable means, a movable actuator for said switching means movable withrdsaid eccentric means upon rotation of said rotatable means, an operator for` said actuator, and means mounting said operator in engagement with said actuator whereby movement of said actuator by rotationof said rotatable means effects move.- mentofA the 'operator 'to an'. adjusted .normal position.

`3. In a limit switch, electrical switching means, rotatable means, means eccentric to the axis of rotation of said rotatable means, a movable .actuatorfor'said switching means pivotally mounted upon said eccentric `means and movable therewith upon rotation of said rotatable means, and an operator for said actuator whereby movement of,

said actuator by 'sai'd ,rotatable meansA eiects movement of the operator to an'adjusted normal position. `v

4. In a limit switch, electrical switching means,

a movable actuatorA for said 'switching means, an

operator for said actuator, 'means "pivotally mounting said actuatoryand meansfo'r 'bodily moving the pivotal axis of vsaid actuator in ai direction having lat :lea-st a componentf'i'n the direction of movement ofthe operator whereby toV effect movement of the 'switch operator toy .an adjusted normal position.

5. In a limit switch, electrical switching means, a movableactuator for said switching fmeans.'V an operator for saidractuator, 'a rotatable shaft, means pivotally'mounting the actuatoron saidA shaft for norm'alrotatio'n' about an axis eccentric to the yaxis of rotation of said shaft,r and means for 4manually rotating .said shaft to move fthe Y pivotal axis ofthe Vactuatorand effect movement A 2; In a limit switch, electrical switching means,v

of thev operator to an adjusted normal position.

6. In a limit switch, electrical switching means, a movable actuator for said switching means, an operator for said actuator biased into engagement therewith, a rotatable member, a stud threaded into said member and having a collar portion upon which said actuator is pivotally mounted with the pivotal axis ofthe actuator eccentric to the axis of rotation of said member, means biasing said actuator against movement of said operator, and means for manually rotating said rotatable member to move the pivotal axis of the actuator to move the operator to an adjusted normal position.

, 7. In a limit switch, electrical switching means, a movableactuator for said switching means, an operator for said actuator biased into engagement therewith, a rotatable member, a stud threaded into said member and having a collar` portion upon which said actuator is pivotally mounted with the pivotal axis of the actuator eccentric to the axis of rotation of said member,

means biasing said actuator against movementv of said operator, means for manually rotating said rotatable member to move the pivotal axis of the actuator to move the operator to an adjusted normal position, the bias on said actuator being stronger than the bias on saidoperator so as to maintain the actuator in non-operated position while biasing the operator into engagement with the actuator.

8. In a limit switch, electrical switching means having first operating means therefor, an actuator for' said operating means, second operating means for said actuator, means connecting said actuator and said second operating means whereby movement of said actuator effects movement of said second operating means, rotatable means, and mea-ns eccentric to the axis of rotation of said rotatable means and movable thereby to shift the position of said actuator relative to said rst operatingmeans upon rotation of said' rotatable means whereby said second operating means is moved to an adjusted normal position.

9. In a limit switch, electrical switching means having first operating means therefor, a pivoted actuator for said first operating means, second operating means rectilinearly movable 'for rotating said actuator about its pivot to effect operation of said switching means, means connecting said actuator and `said second operating means whereby movement of said actuator effects movement of said second operating means, rotatable means, and means eccentric tothe axis of rotation of said rotatable means and .movable'thereby, said eccentric means effecting movement 'of said pivoted actuator in a direction substantially parallel to the direction of movement of said second operating means upon rotation of said rotatable'means whereby said second operat` actuator whereby movement ofsaid actuator effects rectilinear movement .of said Ysecond 'op-7,

erating means, rotatable means, and 4means* eccentric to the axisof rotation of said rotatable means and movable thereby, said eccentricgmeans. 2efecting movement of said actuator :upon rota- 5 tion of said rotatable means in a direction substantially parallel to the direction of movement of said second operating means whereby said `actuator and said second operating means is moved to an adjusted position without moving said rst operating means.

11. In a limit switch for controlling the movement of a moving machine part and comprising an electric switch and an operator depressed by the machine part to effect the operation of the electric switch, bodily movable means interconnecting said operator and said switch, means for maintaining engagement between said bodily movable means and said operator at all times, and means slidably connecting said bodily movable means and said electric switch whereby said bodily movable means may be positioned without operating said electric switch, and means for effecting movement of said bodily movable REFERENCES CITED The following references are of record in the le or" this patent:

UNITD STATES PATENTS Number Name Date 1,981,996 Fjellstedt et al Nov. 27, 1934 2,236,680 Fry Apr. 1, 1941 2,289,643 Furnas et al July 14, 1942 2,328,266 Durbin Aug. 31, 1943 2,425,190 Johnson et al Aug. 5, 194'? 2,460,695 Hennessy Feb. 1, 1949 

